PDF(Pubmed)
Abstract：
Host range specificity is a prominent feature of the legume-rhizobial symbiosis. Sinorhizobium meliloti and Sinorhizobium medicae are two closely related species that engage in root nodule symbiosis with legume plants of the Medicago genus, but certain Medicago species exhibit selectivity in their interactions with the two rhizobial species. We have identified a Medicago receptor-like kinase, which can discriminate between the two bacterial species, acting as a genetic barrier against infection by most S. medicae strains. Activation of this receptor-mediated nodulation restriction requires a bacterial gene that encodes a glycine-rich octapeptide repeat protein with distinct variants capable of distinguishing S. medicae from S. meliloti. This study sheds light on the coevolution of host plants and rhizobia, shaping symbiotic selectivity in their respective ecological niches.
摘要：
宿主范围特异性是豆科植物-根瘤菌共生的突出特征。黑根瘤菌和药草根瘤菌是两个密切相关的物种，与紫花苜蓿属的豆科植物参与根瘤共生，但是某些紫花苜蓿物种在与两种根瘤菌物种的相互作用中表现出选择性。我们已经鉴定出一种Medicago受体样激酶,可以区分两种细菌，作为遗传屏障，抵抗大多数药用链球菌菌株的感染。这种受体介导的结瘤限制的激活需要一个细菌基因，该基因编码富含甘氨酸的八肽重复蛋白，该蛋白具有能够区分S.medicae和S.meliloti的不同变体。本研究揭示了寄主植物和根瘤菌的协同进化。在各自的生态位塑造共生选择性。
